iPhone fails to resolve DNS on cellular data and wifi

Question

Level 1

8 points

iPhone fails to resolve DNS on cellular data and wifi

Since upgrading to iOS 8, my iPhone has been dropping Internet connection every couple of days. After troubleshooting, it seems that it no longer attempts to resolve DNS. Using the NetTools app, I can ping by IP address just fine, but the phone will not resolve DNS.

This happens on both wifi and using cellular data.
Switching between the two does not resolve the issue.
Turning wifi off and back on does not resolve the issue.
Putting the phone in airplane mode for a period of time and then trying again does not resolve the issue.
I have reset the network settings on the phone and this has not resolved the issue.
At this point, only rebooting the phone will fix the DNS issue.

This seems to occur every couple of days, but I've not been able to establish a regular pattern yet.

This did not happen prior to upgrading to iOS 8, and I'm currently running 8.0.2 on a 5S.

Again, this happens on both wifi and cellular data, and would appear this point to be a problem with an iOS DNS client service.

Anybody have similar issues or a fix for this?

iPhone 5s, iOS 8

Posted on Sep 27, 2014 11:23 AM

Reply

Answer 1

RLMCN

Level 1

0 points

Oct 8, 2014 10:19 AM in response to Jim Muckian

Nearly the same issue here. Since the upgrade to iOS 8.0.2, on my iPhone 4s:

- Access to Internet using cellular data works.

- Access to Internet using WiFi is unstable, but works sometimes very slowly.

I have Mac OS X Server 10.9.5 running on a Mac Mini, providing services like Calendar and Contacts synchronization. It seems that iOS is now unable to resolve addresses from this server. Synchronization and profile management stopped working. I tried several solutions found on the Web, without success.

A first generation iPad is still getting synchro from this server.

I'm considering downgrading.

Reply

Answer 2

Jim Muckian Author

Level 1

8 points

Oct 13, 2014 3:31 PM in response to Jim Muckian

It seems that this is possibly related to our wifi controllers at work. The wireless controllers are Cisco 5508s. After the iPhone connects to my work wifi, at some point DNS will fail. This doesn't happen immediately, but sometime within a day or two it will fail. I see today that the last time it worked (based on mail sync) was 11:52am. It's now 3:26 and DNS has gone bye bye.

DNS is done for good though, unless I reboot. I can leave wifi and switch back to LTE, but DNS is still done for. Not sure what the deal is. We have multiple WLANs setup on multiple SSIDs using different security and it happens on multiple WLANs. Both are configured with WPA2-Enterprise and AES. One is 802.1x and another is a PSK. Both will cause the failure.

If I don't connect my iPhone to these WLANs, the issue does not occur. But, the battery will drain quickly hunting for cell signal.

Reply

Answer 3

rswan551

Level 1

0 points

Feb 6, 2015 2:47 PM in response to Jim Muckian

I have the identical same issue. All the same bulleted issues. I have a iPhone 6 and did not notice the problem until iOS 8.0.3. Did you ever find a solution?

Reply

Answer 4

Feb 23, 2015 5:19 AM in response to Jim Muckian

I have the same issue and got it escalated through apple support. I ended up getting a replacement iPhone5s last week, but I have already seen the issue once since then. It looks like a lot of people are having the same issue: iPhone 6 internet problems (not just WiFi)

I found your post because I also noticed that it is a DNS issue which I confirmed by connecting successfully to http://74.125.226.38 while connections to google.com fail. I will bring this up again with support and see if they can figure it out.

I also submitted a bug report. Have you tried that route?

Reply

Answer 5

rswan551

Level 1

0 points

Feb 23, 2015 6:02 AM in response to TactitionProgramming

I may have solved my problem. I have 2 WIFI networks setup (Work and Home). I did 2 things and its been stable for two weeks. It normally craps out every 4 or 5 days. 1) I went into settings and reset the network. Next 2) I added in my work WIFI and last I added my home WIFI. When I added my home WIFI I also changed the DNS setting to the Google public DNS IP 8.8.8.8 and 8.8.4.4 and took out my routers IP.

I was thinking may be the DNS IPs weren't getting updated as it switch from WIFI to WIFI. The Google ones are available all the time on all WIFIs.

My next step is to change it back an see if the problem reappears.

Reply

Answer 6

Feb 27, 2015 5:42 AM in response to rswan551

I tried the google dns servers and still had the issue with my phone. I have been talking to Apple tech support more about this and they are pushing it up to the engineering team, but don't have a good answer yet.

My phone is on T-Mobile. Is yours the same, or a different carrier?

My phone is a 5s with Model number NE296LL/A (in settings, general, about)

Let me know what phones you have, and I will pass the info along and try to get this fixed.

Thanks,

Chris

Reply

Answer 7

rswan551

Level 1

0 points

Feb 27, 2015 7:11 AM in response to TactitionProgramming

iPhone 6, with Verizon and its still working since I made the change.

Bob

Reply